Piston



May 15, 1934.

P. M. FRI-:ER 1,959,023

PIsToN Filed Aug. e, 1932 2 sheets-sheen 1 l @MMM/MM May l5, 1,934., A 1:` M, FREER 1,959,023

PISTON Filed Aug. 8, 1932 2 Sheets-Shee 2 Patented May 15, 1934 UNITED STATES PATENT OFFICE Claims.

The invention relates to pistons and refers more particularly to pistons of that type having separately formed skirts and heads. One of the objects of the invention is to provide an improved 5 construction of piston which provides for unequal expansion and contraction of its head and skirt without affecting its operation. Another object is to provide an improved construction of piston in which the head and skirt are restrained from l0 all relative movement other than in a radial direction. Further objects are to provide a piston so constructed that its parts may be readily and economically manufactured and assembled; that its skirt may be sufficiently exible to conform to the wall of the cylinder in which it may be located; that a simple wrist pin stop may be embodied therein; that a simple stop for the means which secures its head and skirt together may beemployed; and that its skirt may be formed of separately formed sections and these sections may be secured together by means forming part of the means for securing its skirt to its head.

These and other objects of the invention will become apparent from the following description, taken in connection with the accompanying drawings, in which Figure 1 is a longitudinal section through a piston showing an embodiment of my invention; Figure 2 is a cross section on the line 2-2 of Figure 1;

' Figure 3 is an elevation, partly in section, on

the line 3-3 of Figure 2;

Figure 4 is a cross section on the line 4--4 of Figure 3;

A Figure 5 is an elevation of Figure 4 with the skirt removed;

Figures 6 and 7 are details;

Figure 8 is a longitudinal section through a skirt showing another embodiment of my invention.

The piston comprises the head 1 and the skirt 2, the former being preferably formed of a light metal, such as aluminum or an aluminum alloy or magnesium or a magnesium alloy, and being 46 preferably out of engagement with the wall of the cylinder in which the piston operates, and the latter being preferably formed of sheet metal and more particularly sheet steel and being adapted for engagement with the wall of the cylinder.-

The head 1 has the annular portion'3 which is provided with the annular grooves 4 for receiving the piston rings and als has depending from the annular portion the pair of diametrically opposite arcuate walls 5 which decrease in width downwardly and further has the pair of diametrically opposite hubs 6 at the lower ends of the walls and provided with the axially aligned cylindrical bearings '7 for receiving the wrist pin which connects the piston to the connecting rod.

The skirt telescopes over the hubs 6 and the arcuate walls 5 and has its upper end below the annular shoulder` 8 formed upon the head and this skirt is provided with the diametrically opposite openings 9 which are adapted to register with the bearings 7 and are of a size to permit passage therethrough of the wrist pin. The skirt has at its upper and lower ends the inturned annular fianges 10 and 11 respectively, which serve to reinforce the skirt and to maintain the same normally cylindrical, the gauge of the sleet metal, and more particularly sheet steel, forming the skirt being such that the skirt is suiiiciently flexible to conform to the cylinder wall. To give the skirt goed wearing qualities, its outer surface is preferably copper and tin plated.

For securing the head and skirt together, each a is provided with angularly spaced bearings which are arranged in pairs and the bearings of each pair of which are engaged by resilient tubular ,members In detail, the head is provided with the radially extending arcuate and preferably substantially semi-cylindrical bearings 12 which are formed in the opposite sides of the hubs 6 with their axes in the plane extending transversely of the head and through the axis of the bearings '7. The arcuate and preferably substantially semi-cylindrical bearings 13 of the skirt are formed at the opposite ends of the sheet metal and preferably sheet steel members 14, the body portions of whichare arcuate and extend peripherally of and are permanently secured by suitable means, such as welding, to the inner face of the body 15 of the skirt. These members 14 have the inturned :flanges 16 at their ends which are shaped to produce the bearings 13 and the ends of these anges are reinforced by means of the flanges 17 which are also integral with the members 14. With this construction of skirt it Will be seen that the body 15 and the members 14 may be readily and economically formed, since the skirt may be formed by suitable rolling, hooping and welding operations, or by a drawing operation, and the members 14 may be formed by stamping or drawing operations.

Each bearing 13 faces toward a bearing 12 and also toward a radial plane of the piston, which plane extends longitudinally of the piston and each bearing 13 cooperates with its bearing 12 to receive resilient tubular means for eiectively securing the head and skirt together. The means -split, resilient sheet metal sleeve 17 preferably having the portion of its outer face engaging the bearing 12 knurled or roughened to become partially imbedded in this bearing and thereby secure the sleeve to the bearing, so that it moves therewith. However, the portion of the outer face of the sleeve engaging "the bearingl 13 is smooth, so that this sleeve may move over this' bearing upon relative expansion .or contraction of the head and skirt. 18 is a resilient coil under radial compression within the s1eeve'17, the radial compression being such that it maintains atight engagement with the sleeve and the sleeve in turn maintains a tight engagement with the bearings l2 and 13 at all times, irrespective of the relative expansion and contraction of the head and skirt.

These resilient coils are each provided with an inturned portion at one end and a shoulder at the other end for engagementwith a suitable tool for winding up and compressing prior to insertion into the sleeve, the body 15 of the skirt being provided with the openings 19 which register with the pairs of cooperating bearings and are of a size to provide for the passage therethrough of the sleeves and the resilient coils.v

With the arrangement as thus far described, it will be seen that the head and skirt have angularly spaced arcuate bearings which are arranged in pairs with a bearing of the head opposed to a bearing of the skirt, and the bearings of each pair facing toward each other and a radial plane of the piston. It will also be seen that with this arrangement the bearings ofleach pair are coextensive or substantially so, sothat all the convolutions of the resilient c oll or 'the total length of the longitudinally split sleeve act upon both bearings. With this arrangement, it will further be seen that the head and skirt are retained from all relative movement other than in a radial direction and also that unequall expansion and contraction of the head and skirt are provided for without affecting the operation of the piston. Still further, while the upper end of the skirt is preferably clear of the annular shoulder of the head, the two may, if desired, be readily brought together by slightly increasing the length of that portion of the skirt between its upper end and the plane passing through the axes of its bear- 11188 For the purpose of retaining the head and skirt securing means from disengagement from the bearings in aradial outward direction of movement and also for the purpose of Iretaining the wrist pin from disengagement from the bearings in the hubs in a radial outward direction of movement., I have provided the stops 20 between the hubs and the body of the skirt and extending across the openings 9 in the body of the skirt. Each stop is in the nature of a stiff resilient wire having the rounded end portions 21 which are adapted upon iiexing of the stop to engage the portions of the bearings 13 adjacent the body of the skirt. Each stop also has preferably intermediate its ends the depending loop 22 which at its lower end extends below the opening 9 to engage the inner face of the body of the skirt.

As shown in Figure 8, I have provided a skirt body which is formed of sheet metal and preferably sheet steel in the two semi-cylindrical sections 23 and 24 and having abutting edges and these sections are secured together by the sheet metal and preferably sheet steel members 25 having at their opposite ends the radially extending vamistosa arcuate bearings 26. These members 25 with the bearings 26 correspond to the members 14 with the bearings 13, but preferably have at the junction of the sections 23 and 24 an increased width formed by the upwardly and downwardly extending projections 27 and 28 respectively. These members 25 are iixedly secured to the sections 23 and 24 as by welding and they in turn assist in securing the sections 23 and 24 together. In addition to these members, I have provided the upper and lower members 29 and 30 which are arcuate shaped and extend across the junction between the sections 23 and 24 and which are fixedly secured as by welding to these sections and in turn assist in iixedly securing these sections together.

What I claim as my invention is:

1. In a piston, the combinationv with a head having angularly spaced bearings, of a skirt having cooperating angularly spaced bearings, said bearings of said head and skirt being arranged in pairs with the bearings of each pair facing oppositely and toward a radial plane of the piston extending longitudinally thereof, and means engaging the bearings of each pair for securing said head and skirt together.

2. In a piston, the combination with a head having angularly spaced bearings, of a skirt having cooperating angularly spaced bearings, said bearings of said head and skirt being arranged in pairs with the bearings of each pair substantially co-extensive and facing toward a plane radially and longitudinally of the piston, and means engaging the bearings of each pair for securing said head and skirt together.

3. In a piston, the combination with head and skirt members having cooperating angularly spaced bearings arranged in pairs with the bearings of each pair facing oppositely and toward a radial plane of the piston extending longitudi- 115 nally thereof, and means engaging the bearings of each pair for securing said head and skirt members together, said securing means comprising'a member secured to one of said head and skirt members and movable relative to the other. 120

4. In a piston, the combination with head and skirt members having cooperating angularly spaced bearings arranged in pairs with the bearings of each pair substantially co-extensive and facing toward a plane radially and longitudinally 125 of the piston, and means engaging the bearings of each pair for securing said head and skirt members together, said securing means comprising a member secured to one of said head and skirt members and movable relative to the other. 130

5. In a piston, the combination with head and skirt members having cooperating angularly spaced bearings arranged in pairs with the bearings of each pair facing oppositely and toward a radial plane of the piston extending longitudinally thereof, and a resilient tubular member engaging the bearings of each pair for securing said head and skirt members together.

6. In a piston, the combination with head and skirt members having cooperating angularly spaced bearings arranged in pairs with the bearings of each pair facing oppositely and toward a radial plane of the piston, a longitudinally split sleeve, and a radially compressed resilient member in said sleeve.

7. In a piston, the combination with head and skirt members having cooperating angularly spaced arcuate bearings arranged in pairs with the bearings of each pair facing oppositely and toward a radial plane of the piston, a longitudi- 150 nally split sleeve secured to one of said head and skirt members and movable relative to the other, and a radially compressed resilient member in said sleeve.

8. In a piston, the combination with head and skirt members, said head member having wrist pin receiving hubs and bearings formed entirely in said hubs, said skirt member having cooperating bearings and said bearings of said head and skirt members being arranged in pairs, and means engaging the bearings of each pair for securing the head and skirt members together.

9. In a piston, the combination with head and skirt members having angularly spaced bearings, said bearings of said head and skirt members being arranged in pairs with the bearings of each pair facing toward each other and toward a plane extending longitudinally of the piston, and means engaging the bearings of each pair for securing said head and skirt members together.

10. In a piston, the combination with a head having angularly spaced bearings, of a skirt body, peripherally extending members secured to said skirt body and having bearings at their opposite ends, said second mentioned bearings being angularly spaced and cooperating with said rst mentioned bearings, said first and second mentioned bearings being arranged in pairs, and means engaging the bearings of each pair for securing said head and skirt body together.

PHELPS M. FREER. 

